The objective of the proposed research is to investigate the fundamental mechanisms involved in the assembly of the carbohydrate portion of the sugar-bearing proteins synthesized by the milk secreting mammary tissue of the cow. Sugar-bearing proteins play extremely important and diverse functions in biological systems. This includes involvement in hormone-cell interaction, enzyme function, cell-cell recognition, virus-cell interaction, blood clotting and blood clot prevention, tissue graft rejection, atherosclerosis and malignancy.